The present disclosure relates to an electric power system and an image forming apparatus having the electric power system, and more specifically, to a technology for controlling an oscillation operation of a switching power supply of a power supply according to a pulse signal.
In the related art, a technology for controlling an oscillation operation of a switching power supply of a power supply according to a pulse signal is known. In such a related art, a switch control unit is provided so as to control oscillation of a switching power supply according to a control pulse signal which is supplied from a mode control block (a power supply key control IC), and stops the output of the switching power supply according to the control pulse signal.
If disturbance noise is generated, for example, during an operation of an electric power system, it is feared that the switch control unit (power supply control IC) may mistakenly recognize the disturbance noise as a control pulse signal for switching the oscillation operation, and stop the oscillation of the switching power supply.